Program Project (645PP): Neurochemical Control of Memory in Aging Schizophrenics. An important model for preventing or treating the clinical symptoms of schizophrenia is derived from the NMDA glutamate receptor hypofunction (NRHypo) hypothesis. the circuitry proposed for the NRHypo hypothesis is based on evidence that specific receptor agonists and antagonists can block the neuropathologic impact of NRH on cortical neurons. Previous experiments demonstrating treatments that block NRH-induced neuropatologic changes provide a rationale for testing efficiacy of those treatments in blocking he clinical manifestations of NRH induced by the NMDA glutamate receptor antagonist, ketamine.